In a dry room or car interior, it may require a humidifier for humidifying the air for comfortable living or driving. However, it is not available or it is difficult to obtain a portable mini humidifier from the commercial source.
Even a prior art of U.S. Pat. No. 4,085,893 disclosed an ultrasonic humidifier for atomizing water or other liquid, which however has the following drawbacks:    1. A water supply system including conduit or tube must be provided for supplying the water to be atomized by an ultrasonic vibrator, thereby causing a complex structure and unsuitable for portable uses.    2. There is no sensor provided for sensing the humidity in the air.    3. There is also no indicator showing the water content in a water supply system.
The present inventor has found the drawbacks of the prior art and invented the present portable humidifier.